Their life span varies but few can be termed even semi-permanent. Those constructed of solid timber, treated with wood preservative before erection and set deeply in the ground or in solid bases, can last for some years. They are then useful as supports for climbing or trailing plants that add to the attraction of the garden and that may be the chief reason for their use. It must be remembered that the more solid the fence or screen the greater the wind turbulence on the sheltered side and the greater the difficulty in keeping such structures erect in the strongest gales. Wire or plastic netting or strips of plastic on metal or wooden uprights are purely temporary means of providing shelter from wind, defining a boundary or screening an eyesore. They may provide support for temporary climbing plants or protection for a more permanent hedge but they are nearly always unsightly and better avoided wherever possible. Walls of brick or concrete, solid or open and in a range of designs, are much more permanent and can fill many requirements in suitable situations, such as when they form extensions to the house or other buildings or enclose the most formal parts of the garden. There, they may cut off the winds that whistle round corners, screen ugly outbuildings or unsightly views. They may be better for these purposes than even the toughest trees or shrubs which may be impossible to grow in such circumstances. Many old walls remain in older gardens, and, like those more recently erectecf, they not only provide shelter but valuable space against which to plant and on which to train fruiting plants which thrive better in such conditions. They may also provide protection for many climbers, trees and shrubs which would be unlikely to survive without such shelter and support. The importance of providing artificial screens with adequate support must be emphasised again if these are to do their job properly and remain upright in the strongest of gales. All types of fences need strong posts set in solid foundations and adequate ties. Additional buttresses may often be needed for single walls and all must be set on solid foundations. In many situations living hedges and screens are better than artificial barriers. Patience is needed while they mature, but many can last a lifetime and add beauty to the garden.CULTURAL CONSIDERATIONS The detailed needs of each plant will be considered when discussing their uses, but in general it can be said that the greater the depth of soil the better the growth and the longer the life of a hedge. For all but a very few species adequate draining to prevent waterlogging is essential. Where drainage is suspect and wet conditions are likely it is often better to limit the plant choice to those that thrive in such conditions rather than to struggle to drain the ground and still run the risk of failure. For all hedges proper soil preparation is necessary in order to provide good rooting conditions. All weeds must be removed.